CVE-2021-29951 Explained : Impact and Mitigation

A vulnerability has been identified in Mozilla products, impacting Thunderbird, Firefox, and Firefox ESR versions. The issue allowed normal remote users to start or stop the Mozilla Maintenance Service, affecting Windows systems prior to build 1709.

Understanding CVE-2021-29951

This CVE encompasses a security flaw in Mozilla products, potentially exploited by domain network users.

What is CVE-2021-29951?

The vulnerability allowed BUILTIN|Users to access and control the Mozilla Maintenance Service, impacting Thunderbird < 78.10.1, Firefox < 87, and Firefox ESR < 78.10.1.

The Impact of CVE-2021-29951

This vulnerability could have permitted unauthorized manipulation of the Mozilla Maintenance Service, hindering browser update functions on older Windows systems.

Technical Details of CVE-2021-29951

The following technical aspects further describe the CVE.

Vulnerability Description

The flaw enabled BUILTIN|Users to control the Mozilla Maintenance Service, affecting specific versions of Thunderbird, Firefox, and Firefox ESR.

Affected Systems and Versions

Impacted versions include Thunderbird < 78.10.1, Firefox < 87, and Firefox ESR < 78.10.1 on Windows systems predating build 1709.

Exploitation Mechanism

Attackers with access to the domain network could start or stop the Mozilla Maintenance Service, potentially disrupting update functionalities.

Mitigation and Prevention

Minimize the risk associated with CVE-2021-29951 by following these security practices.

Immediate Steps to Take

Ensure systems are updated and operate on secure Windows builds to mitigate the vulnerability’s impact.

Long-Term Security Practices

Implement robust access controls and monitor service configurations to prevent unauthorized service manipulation.

Patching and Updates

Apply relevant patches and updates provided by Mozilla to address and mitigate the CVE-2021-29951 vulnerability.